Technology-grade grown diamonds (often referred to as optical-grade CVD diamonds) have become an essential engineering material in the optics field. Unlike gemstone diamonds, which are valued for their aesthetics, technology-grade diamonds are grown via Chemical Vapor Deposition (CVD) to maximize specific physical properties like thermal conductivity and spectral transparency.
Here is how they are used in the optics field:
1. High-Power Laser Windows
The most common use of optical-grade diamond is as a window for high-power industrial lasers.
Thermal Management: Diamond has the highest known thermal conductivity allowing it to dissipate the intense heat generated by kilowatt-level lasers.
Low Absorption: It has a very low absorption coefficient in the infrared (IR) spectrum, which prevents “thermal lensing”—a phenomenon where an opticdeforms due to heat, distorting the laser beam.
2. Multi-Spectral Windows and Lenses
Diamond is one of the few materials that is transparent across a massive range of the electromagnetic spectrum.
Aerospace & Defense: Used in sensor windows for missiles and aircraft that need to “see” in multiple wavelengths
(e.g., visible light and long-wave infrared) simultaneously.
Harsh Environments: Because diamond is chemically inert and the hardest known material (Mohs 10), these windows can withstand sand erosion, salt spray, and corrosive chemicals that would destroy glass or sapphire.
3. Spectroscopy Components
In FTIR (Fourier-Transform Infrared) spectroscopy, diamond is used as the internal reflection element (IRE) or as a sample window.
Durability: It allows researchers to press abrasive or hard samples directly against the diamond surface with high pressure to ensure good optical contact without scratching the optic.
Chemical Resistance: It is impervious to almost all acids and solvents, making it ideal for analyzing “dirty” or reactive chemical samples.
4. High-Energy Beamlines (X-rays and Synchrotrons)
At synchrotron facilities and X-ray free-electron lasers, diamond is used for:
Monochromators: Selecting specific X-ray wavelengths.
Beam Position Monitors: Because diamond is a low-atomic-number (low-Z) material, it is relatively transparent to high-energy X-rays, allowing it to stay in the beam path to monitor position without significantly attenuating the light.
5. Advanced Raman Lasers
Diamond is considered the “ultimate laser crystal” for Raman lasers.
It has a very high “Raman gain” which allows engineers to create lasers that shift light to new wavelengths (frequency conversion) with extremely high efficiency and beam quality.